Mushoku Tensei: The Key That Connects Hearts
by roxasora14
Summary: Sora lived and died as a hero, now he's reincarnated in a new world and it seems that even there destiny still have plans for him. (Kingdom Hearts x Mushoku Tensei)
1. Chapter 1

**So… yeah, I just came up with this crossover idea between Kingdom hearts and this light novel/web novel I just started reading "Mushoku Tensei -Isekai Ittara Honki Dasu" is just as the premise of this fanfiction the MC get reincarnated in a new world and so as to not live with regrets he tries his best to life fully, in this fanfiction the MC gets replaced by Sora and well there will be a few more changes across the way. So… yeah review if you enjoyed this chapter and check out the original works.**

 **Disclaimer: Kingdom hearts belongs to Disney and Square Enix and Mushoku Tensei belong to Rifujin na Magonote**

* * *

"So this… is the end… huh…"

I say as I sit in the middle of the keyblade graveyard, my kingdom key embedded into the earth like a tombstone.

"What a joke…"

To think this would be my end. I almost didn't have strength to reach this place… perhaps I should have return to destiny islands one more time… nah, I wouldn't like for Kairi and Riku to see me this way.

Oh, right I haven't introduced myself yet; my name is Sora, keyblade wielder by profession actually I think me and King Mickey are the only active keyblade wielders right now the others retired a few years ago. I'm currently 50 years old even though if you look at me you'll probably think I'm around 90. You see when I was young and even now I still use something called DRIVE it was a power a fairies friends of mine gave me, what it allowed me to do was to break my limits and achieve my maximum potential, however that came with a price my body begun to age rapidly when I became 20 years old, back then there was hope to stop this situation but… I couldn't give up that power…

"Well, it's not like I regret it…" I say as I look up at the sky.

After all, even back then there were still many people who needed help and even though it may sound arrogant I like to think I was able to help them with these powers of mine… I still remember how most of my friends were angry at me for choosing what I did… Riku, Kairi, Ventus, Terra, Aqua, Xion, Roxas, Donald, and Goofy, even Lea and I was never that close to him. I lost all contact with them a few years ago…

"I really should have gone see them one more time." I say closing my eyes

From the last time I saw Riku and Kairi, I think they were dating. I hope they are not married, I would feel horrible if I missed my best friends wedding because of a dumb argument.

*sigh*

It was no use; after all I just felt my body starting to fail me this morning… huh? You want to know what I mean by failing; well that easy my body just starts disappearing, it seems keyblade wielders don't leave anything behind but their keyblades.

I can already feel my lower body gone… this is really scary… but, well I lived the best way I could, trying to help as many people as I could, enjoying every second… I think I lost a few things in the way but I also gained many things.

"Yeah… I have no regrets…"

.

.

.

.

.

But I guess this is more of a wish, if I could do it all over again, this time with my own strength not the power of the keyblade but my own power, to be able to make friends again, to be able to save people again, to be able to fight for what I believe again… to be able to smile under the same sky with everyone again… that is my wish, I guess it's just the normal wish of a normal person…

"Goodbye, everyone" my voice is the last thing I hear before losing consciousness.


	2. Chapter 2

**Disclaimer: Kingdom hearts belongs to Disney and Square Enix and Mushoku Tensei belong to Rifujin na Magonote**

* * *

There is nothing but white… white as far as I can see… and I don't think I even have eyes to see with. It's warm and relaxing… so this is the afterlife…

"Ohhhhh, come on! You died! But how?! And I didn't even get to know you this time around." I hear a voice say strangely close to me, considering that I don't have ears to hear with.

"Humph… well, what am I supposed to do with you now?"

I don't think he/she cares for my opinion but I still try to say something, I mean I just died so cut me some slack at least, however nothing comes out of my mouth… that's right I probably don't have a mouth, for that matter I don't think I even have a body.

"Well, since we didn't meet in this life then perhaps in the next one, what do you say? I still want to have some fun with you…"

I suddenly feel weird, something… something is pulling me away from here…

" _ **Now wake up."**_

* * *

When I open my eyes again, I'm looking at a young blonde woman gazing at me.

"…"

She says something but I can't understand.

At her side is a strong looking man around the same age with brown hair giving me a stiff smile.

"Ah… ah…" I try to say something, but that's the only thing that comes out.

They hear me and then give me a small smile.

"…"

"….."

"…."

They start talking to themselves again. This is scary, really scary, I thought that I was dizzy from waking up but I REALLY can't understand them, what's more I can't move, I feel my limbs so, why can't I move?!

"…" a third voice enters the room; this time is a woman with black hair, glasses and wearing a maid outfit.

Dammit, I'm getting tired; I want to go back to sleep… it should be fine, right? Even though I don't know these people I feel safe with them, my heart is telling me they are people I can trust… so for now I'll just sleep. As I'm thinking this the brown haired man starts carrying me in his arms. I kinda wonder how's that even possible, after all I'm an adult man and I'm quite tall as well… oh, it doesn't matter I just want to sleep.

* * *

 _Three years later:_

"Ahhh… the breeze feels great…"

It's been three years since I was reborn/ reincarnated in this world.

It was really disorientating at first, being a baby and all that, accepting the fact that I had died was also certainly difficult, but after three years you get accustomed to it. The first year in this new world felt like a dream, like if at any moment I would get pulled away from here only to wake up at the keyblade graveyard again or even thinking that this was actually heaven. But, no, I truly was reborn in a new world with the memories of my past life for some reason I don't know, yet. In any event I'm not "Sora" anymore in this new life I'm Sora Greyrat the son of Zenith and Paul Greyrat, why is my name Sora in this world as well? I have no idea but I'm not complaining it makes things easier for me and even though my name is the same my appearance isn't, my usual blond-brown spiky hair is now a far less spiky tea-brown and my usal sky blue eyes are now a light green just like my dad, that being said the whole name thing does worry me it just feels like someone is toying with my life but I try not to think much about it. I live in Buina Village in the region of Fedoa, it a small rural town that is surrounded by a dense forest and it's mostly know by the wheat it produces and a special type of flower that grows around here.

How do I know all this? you ask. Well, easy I read it in a book, while it's true that in this world owning books seem to be more of a luxury we do have a few at home. Ah, but I hear you ask again: how come you can read, you are only three years old? Well, I'm technically 53, so there you have it.

"… I really love this place…"

I sigh contently, this place reminds me so much of Destiny Islands, a tranquil home with a loving family and we even have a maid, her name is Lilia, she seems really strict on the outside but she's always taking care of me. I feel bad for her and mom when I escape of the house to come to this place, it's a robust tree in a hill overlooking the town, but they know where to find me so there shouldn't be any problem, the first time I left the house was quite a mess…

"Well, doesn't matter, I'll just take a nap…"

With that I close my eyes and drift into sleep.

*sniff, sniff* Is smell a familiar scent in the air.

I open my eyes and sit up in a rush.

"This scent… it can't be…"

No, there is no way they are here… the heatless, it's impossible…

"… It's coming from the woods…"

The heartless shouldn't be active anymore, I made sure of that… but even though I know that, my hand has already grabbed my toy sword and my legs are already moving towards the forest.

This is a bad idea, the *me* from before the reincarnation could deal with heatless as if they were ants but the *me* now is a child of three years only armed with a toy sword made from the broken practice swords of dad and with magic that I can't use properly.

"Well, the best option right now is to check if there are truly heatless here and if there are go talk to Paul."

I say that in voice so soft that only I can hear as I enter the forest. In this forest magical creatures appear (magical creatures are animals exposed to magical energy that mutate and start attacking humans) so that could be what I felt, in any case I'll go back home and tell dad since he is the knight in charge of defeating any magical creature in the forest that represents a danger to the village. Actually this forest is guarded by many people throughout all day and night but well there is only so much you can do, I can only hope that if there really are heartless none of the people are hurt…

"…help! Someone please! Ahhhh!" I hear a small voice from deeper in the forest.

With just that any previous thought of going back home are completely forgotten and I start running, my hands are shaking and I can barely grip my sword but if I turn back now someone might get hurt… no, I won't let it happen. The me from before and the present me none of us will have any regrets, so I'll always follow my heart and right now it's telling me to help someone.

As I keep running, I finally see it a shadow about double my size.

"HAAA!" I jump and smash my toy sword on top of it.

The shadow sees my attack and returns to the earth and retreat into the forest.

"Weird…"

Why did it escape? Heartless never scape… perhaps it really wasn't a heartless, no it doesn't matter right now.

"Hey, are you alright?"

I turn around to see a kid around my age in the ground with pointy ears and green eyes, there is a wound in his back not deep enough to kill him but it is bleeding, he is probably just fainted from fear.

"Cure" I see the flower petals appear above him, knitting the wounds together.

"Come on, wake up…" I move him in hopes of awaken him. It would be dangerous if the heartless return.

"*groan* what happened…?"

"You were attacked by something, I healed you but we should leave now." No use in telling him about the heartless since it's already gone.

"O-okay…" We both stand up and get ready to leave but… "Behind—"

Before he even finishes his sentence, I'm already parrying the strike from the heartless; it tried to attack me from behind but seems that my instincts are still in top form. The heartless after failing his attack jumps backwards and lands between us and the exit to the forest.

The kid grabs the sleeve of my t-shirt really tightly and I turn to look at him, he is obviously really scared and tears are threatening to fall from his eyes.

"H-hey, c'mon don't cry. We are gonna be fine, he is just one we can totally outrun him." I give him my most comforting smile.

However just as I say that nine more shadows appear by the side of the first one. And his grip on my t-shirt tightens.

"Just stay behind me, I'll protect you." I move him from my side to my back and slowly retreat until our backs are touching a tree.

Like this we only have to worry about our front.

The heartless watch us wearily, perhaps thinking we're going to attack however as soon as one of them realizes that we're defenseless, all of them lunge at us. In that moment I put my toy sword in front of me and…

"PROTECT!" I command.

"Eekkk!" I hear him scream as he buries his face in my back

Their claws clash against the protect spell. The spell is barely holding up and is not even fully formed, instead of a full dome is only a semi dome that barely reaches our back, I'm really glad the heartless are not exactly the most bright of creatures or we would probably be dead already.

"Guh…!"

I feel the spell almost breaking and I reinforce it once again. I click my tongue, at this rate the best we can hope to survive is to wait for mom or Lilia to realize I'm not in my usual spot and send dad to search for me or to wait for this kid parents to also search for him… but, I'll probably won't be able to hold on for long… no, better not to think about that… we'll definitely survive!

Suddenly the heartless attacks stop and they retreat.

"Huh?" I drop the spell to not waste energy but keep my sword in front of me in case they attack again.

The shadows sink into the ground forming a small puddle of darkness and from there a gigantic size claw emerges (or at least gigantic to my size) a Giga shadow appears.

Oh, c'mon I can barely hold my on against one shadow, what am I supposed to do in this situation…

The Giga shadow readies his claw and strike at us.

"PROTECTRA!" the shield reforms once again and… it easily breaks against the strength of the attack, we are left defenseless but it did managed to parry the attack, however the Giga shadow simply backhand us, I manage to wrap my arms around the other kid to protect him, we are throw and clash against a tree.

"ugh…" I unwrap him and stand up dizzily and look towards the heartless, he is just watching us, he knows he has us where he wants us "How are you?" I think I received the brunt force of the attack but you can never be too sure, hopefully he is not too traumatized.

"*sob* *sob*" figures, well this is the correct reaction to almost dying it would be weird if he was laughing or smiling.

"Hey, what's your name?" I turn to look at him with my biggest smile.

"h-huh?" he is definitely confused, after all in this kind of situation where one is about to die smiling is weird but well, smiling in this situations is what I do best. "I-I'm S-Sylphiette"

So that's his name… wait, with a name like that.

"Are you a girl?" I ask.

And she only nods shyly.

I let out a small laugh that seems to confuse her more, can't help it this reminds me of when I meet Mulan way back then.

"My name is Sora, well then S-Sylph-Sylphiet— Mind if I call you Sylphy? Let's be friends?"

"H-huh?"

"Let's be friends from now on, okay? Sylphy" I give her another bright smile.

She simply nods once again.

"Alright then, since we are friends I'll need you to trust me once I turn around I need you to run as fast as you can towards the town, got it?"

"B-but—"

"I'll be fine, you just gotta trust me" I help her stand up "Ready…?"

I don't wait for her answer; instead I turn and start building up energy in my hand. When the Giga shadow lunched us he threw us towards the exit to the forest. But even if we run it will be not enough we're only children we need to stop it somehow.

I hear Sylphy start running and as soon as that happens so does the Giga shadow start charging at us.

My hand is closed with a light blue glow to it. I raise it up in front of me and wait until the heartless is about to ram into me that I open it.

"BLIZZARD!" Cold air explodes around me and frost start to form all around us including the heartless, slowing him down.

I turn and start running, Sylphy is not that far away and it seems she was looking back to make sure I didn't die.

We continue running for what feels like hours even though it not even a minute with the Giga shadow still closely behind us, suddenly in the distance we see two male figures: One of them is dad fully armed with his sword at his side and the other is a blond man with pointy ear. Sylphy run towards the man while I run to dad.

"Sora, what are you doing here?!" Dad says alarmed.

"No time… Monster… behind us…"

Paul gets really serious as he hears the Giga shadow coming for us.

"Rawls, get the kids out of here. I'll take care of this" he says as he unsheathes his swords and gives me a warm smile.

After this both Sylphy and I follow the other man out of the forest.

* * *

 _A few minutes later:_

We three are waiting for dad in the edge of the forest.

It seems Rawls is Sylphy's dad, I heard her call him that, and he is trying to console her daughter after everything she's gone through. He seems like a nice guy and talking about nice guy Paul is still in the forest, he is strong but then again so is the heartless, no wait I can't think like that—

Justas I think that dad appears from the forest with not even a scratch on him… Seem I was worried for nothing.

He looks really serious but as soon as he sees us he gives a smile.

"Paul, were there any more heartless in there?" Rawls asks as Paul gets closer to us, so they do know about the heartless.

"No, there was just the one that attacked them, I search in there for a bit but I didn't found anything, then again heartless are pretty hard to come by so is not that surprising."

"True that, it seems that the heartless tricked Sylphiette into going in the forest with my appearance and after that your son came to save her, we are truly grateful, by the way Sylphiette don't you want to tell him something?"

"A-ah… um…" she looks from her dad to me "Thank you very much! I-I…" She is clearly nervous and is struggling with her words.

"It's okay, after all we're friends." I say giving her a smile and patting her head "Let's get along from now on, okay?"

"Y-yes!" She replies with a smile of her own.

"Well, I'm just glad you both are okay." Dad says while patting my head "Rawls, do you mind informing the town of this incident?"

"Yeah, no problem, I'll leave Sylphiette at home and then I'll go"

"Thanks"

With that we say our goodbyes to Sylphy and her dad and start going back home. I ask dad to carry me on his shoulders since I'm extremely tired from all that happened.

Many things happened today, I realized heartless exist in this world, made a new friend, discovered that I can still use magic and fight for my life, all in a good day work.

"You know while I was checking the forest, there was a part of it that was covered in frost, did the heartless did that?"

For a moment I consider lying but… he is my dad and there shouldn't be any problems even if I tell him.

"No, that was me."

"Hum… I see, how did you do it?"

That I can't tell "I don't know, I wanted to help her, so I imagined a way to stop that monster and simply did it… *yawn*" that's not completely untrue my type of magic was always connected to my heart so that was not a lie… fully.

"I see, so you wanted to help her, huh? You are a good kid." I can see a small smile on his face "Your mom will also be glad that you can use magic."

"Really?! I'm glad…" I say with a smile as I slowly drift into sleep.

Like that another day ended… In this new life… in this new world… of swords and magic…


End file.
